Treatment of motor fuels with aromatic esters



Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE TREATMENT OF MOTOR FUELS WITH AROMATIC ESTERS .Frederic R. Bean, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application July 1, 1938,

7 Serial No. 217,022

8 Claims. (01. 44-9) a deterioration. This produces the formation of color and gummy resinous material within the hydrocarbon as well as reduces the knock ratin 5 and otherwise impairs the product.

I have found that aromatic esters may be produced in accordance with the methods described herein and that these esters may be employed,

with excellent results, for use in stabilizing the various hydrocarbons, motor fuels and the like which normally tend to deteriorate.

This invention has for one object to provide a stabilized motor fuel or other stabilized hydroe carbon liquid, which normally tends to deteriorate. Another object of this invention is to pro-- vide a hydrocarbon fluid stabilized with amino ester containing a 3-5 carbon atom radical such as propionyl or butyryl in the molecule. A still further object is to provide anamino ester par- .0 ticularly saisfactory for use as an agent in motor fuel stabilization. Another object is to provide a motor fuel stabilizer or inhibitor of the structure comprising an ester group attached to a nitrogen atom also having a phenol group and ;5 hydrogen there attached. Still another object is to provide a motor fuel or other hydrocarbon stabilized with amino esters which are only limitedly soluble in water but which are soluble.

in the motor fuel. A still further object is to L0 provide a motor fuel stabilized with at least one of the agents, propyl p-hydroxyphenylamino acetate and secondary amyl p-hydroxyphenylamino acetate. Other objects will appear hereinafter. Inasmuch as I believe that my agents are new [5 chemical compounds, examples are set forth to show the manufacture thereof. It is to be understood that these examples are set forth for the purposes of illustration and are not intended to limit my invention. ;0 My novel aromatic amino esters may be produced by catalytic reaction at'temperatures, for example, not materially greater. than the temperature of a steam bath. In the event reduced pressure or other similar expedients were em- ;5 ployed, lower or modified temperature conditions could also be employed. For a more detailed understanding of my novel stabilizing agents and their manufacture, reference is made to the following, which represents procedure that may be employed for producing certain of my preferred 5 stabilizing agents.

20 gr. of p-hydroxyphenylamino acetic acid were mixed with 250 cc. of secondary amyl alcohol. p-hydroxyphenylamino-acetic acid is a compound comprising the formula:.

n cmcoon and may be obtained from any of the usual 20 sources for use in the present invention. For example, the aforementioned aminoacetic acid may be obtained by reacting p-aminophenol with chloracetic acid. 0r, methods disclosed in the literature may be employed for manufacturing the acid. The alcohols employed are well-known commercial quantities and hence further description is unnecessary. This mixture of the amino acid and alcohol was saturated with hydrogen chloride gas and then warmed on a steam bath under reflux for between 6 and 15 hours. The unreacted alcohol was then distilled ofi leavin the ester hydrochloride as a residue. This residue was then poured into two liters of cold water containing about 1 mole. of sodium carbonate. This step was accompanied by vigorous agitation of the components. The end point was then adjusted until it was neutral to brilliant yellow. Thereafter the ester was filtered off, washed and dried. The ester obtained was secondary amyl p-hydroxyphenylamino acetate melting at approximately 51 C. Another run similar to that described was carried out except that propyl alcohol was employed as the alcohol. In this run propyl p-hydroxyphenylaminoacetate was obtained in substantial yields, this ester having a melting point of approximately 81 C.

Similar procedure may be applied to react p-hydroxyphenylaminoacetic acid and other alcohols to produce my stabilizing agents. It is, of course, understood with respect to such reactions suitable temperature changeswould be made to compensate for the different boiling points of the different alcohols employed and distilling them from the reaction mixture. It is also possible to employ other alkalis than sodium carbonate. For example, potassium carbonate, calcium hydroxide and carbonate, sodium acetate and the like, may be utilized. It is also possible to modify my process in certain other respects. For example, sulfuric acid, phosphoric acids, zinc chloride or other salts, or other suitable esterification catalyst may be employed. Certain of the alcohols employed will carry off the esterification water as an azeotrope.

The esters produced according to my invention may be generically described as comprising an aliphatic ester group attached to a nitrogen atom which also has attached thereto a hydrogen atom and a phenol group. For example, one of my preferred stabilizing agents comprises the structural formula RiNHR, where R may represent a substituted or unsubstituted aromatic group such as phenol. The symbol R1 refers to an ester, for example, such as CHICOOPr where Pr represents propionyl or CHzCOOAm wherein Am represents either'the normal or secondary amyl radical.

The aforementioned esters are preferably added to the freshly produced motor fuel or other hydrocarbon product. Otherwise, in an old or partially aged fuel deterioration would have already taken place to some extent and the product could not be as effectively stabilized. My stabilizers would be added to the motor fuel or hydrocarbons in any suitable manner. For example, when treating small quantities of such materials, the stabilizing agent could be introduced directly there into as small portions while vigorously agitating the material being so treated. In incorporating my stabilizer into larger batches, it could be added on the suction side of a pump in the form of a slurry or by means of other suitable feeding procedure to motor fuel being conducted to storage tanks or the like. It is preferred that-the stabilizer be finally completely dissolved in the motor fuel and usually this can be expedited by some agitation and circulation.

The quantity of the aromatic amino ester which would be added will depend upon the particular type motor fuel or hydrocarbon to be stabilized, the particular ester to be employed, the conditions of storage, and other such factors. Ordinarily, less than 1% or 2% will suffice under all conditions. In many instances less than (based on weight of motor fuel stabilized) will stabilize the fuel'for a desired period.

My new amino esters may be employed' for stabilizing any of the motor fuels comprising hydrocarbons which normally, without some prior treatment or stabilization, undergo decomposition and deterioration. These various hydrocarbon materials may also be referred to as gasoline, petrol, or under various trade names, and usually comprises unstable constituents such as unsaturated hydrocarbons.

My stabilizers are also useful for stabilizing various fuels produced by cracking high boiling point hydrocarbon oils or produced by destructive distillation of substances containing carbon and hydrogen, such as the various liquid fuels produced from coal, peat, and the like. My novel aromatic amino esters may also be employed in treating the various hydrocarbon fuels produced from the polymerization of unsaturated hydrocarbons to motor fuels.

In addition to having the property of being capable of use in various hydrocarbon products for stabilization purposes, my novel stabilizing per sq. cm.) pressure.

agents are particularly eflicient and potent when so employed. The induction period of my agents as compared with the induction period of certain stabilizers commercially available, not only compared favorably but in some instances showed a higher period.

Among the methods of testing which may be employed, reference is made to what is known as an accelerated oxidation test. While there are several ways of carrying out such a test, the method described by Egloi'f, Morell, Lowry and Dryer in Industrial and Engineering Chemistry, vol. 24, pages 1375-1378 (1932) is very satisfactory and widely used. Briefly, the described method is as follows: A sample of the motor fuel or hydrocarbon products to be tested, in an open eight-ounce bottle, is placed. in a suitable metal bomb surrounded by a water-bath. Oxygen is introduced to pounds per square inch (7 kg. The bath is then heated by steam to 100 C. As the temperature increases the pressure rises, reaches a maximum and continues near this maximum for a shorter or longer period of time. The test is continued for four hours or until a break in the pressure curve is noted. The period from slightly before attainment of maximum pressure (approximately 15 minutes from the beginning of heating) until more than a slight drop in pressure takes place (usually a sharp break in the pressure curve occurs) is recorded as the induction period.

When tested by such tests, my novel agents were found to give results within the range considered satisfactory for motor fuel stabilization. The conducting of such tests on my amino esters, is also of assistance to some extent in determining the minimum quantity of any particular amino ester which should be added to a larger quantity of said fuel for stabilizing the fuel for a predetermined period.

While in the preceding description I have described the more or less direct incorporation of the stabilizing agent with the hydrocarbon, the agent may be dissolved in solvents therefor, as the various lower aliphatic alcohols and the like, and the resultant liquid added.

It is also further apparent from thepreceding that my invention is susceptible of some modification, hence, I do not wish to be restricted excepting insofar as is necessitated by the prior art and the spirit of the appended claims.

What I claim and desire to be secured by Letters Patent of the United States is:

1. A motor fuel comprising hydrocarbons and which normally tends to deteriorate, containing a lower monoalkyl ester of p-hydroxyphenylaminoacetic acid in which the alkyl group contains at least 3 carbon atoms, in an amount sufilcient to substantially inhibit said deterioration.

2. A motor fuel comprising hydrocarbons and which normally tends to deteriorate, containing an ester resulting from the reaction of an organic acid of the formula HOOCCHNHR, where R represents a phenol group, and a lower aliphatic alcohol having 3-5 carbon atoms, the ester being present in an amount sufficient to substantially inhibit the deterioration.

3. A composition of matter comprising a motor fuel which normally tends to deteriorate, containing a propyl ester of p-hydroxyphenylaminoacetic acid for stabilizing the fuel against said deterioration.

4. A composition of matter comprising a gumforming motor fuel and at least one lower monoalkyl ester of p-hydroxyphenylaminoacetic acid in a quantity sufllcient to appreciably retard the gum formation of said fuel.

5. A motor fuel addition agent essentially comprising an ester having the structural formula RINHR wherein It may represent a substituted or non-substituted aromatic group such as phenol and R1 represents an ester containing a lower alkyl radicle, said addition agent being in the form of a slurry with a solvent for the ester, which solvent is at least partly miscible with motor fuels.

6. A motor fuel addition agent essentially comprised of a lower monoalkyl ester of p-hydroxyphenylaminoacetic acid in which the alhl group has at least 3 carbon atoms.

'7. A process for preparing a stabilized motor fuel, which comprises dispersing in a motor fuel which normally tends to deteriorate, at least one lower monoalkyl ester of p-hydroxyphenylaminoacetic acid.

8. The method of reducing the gum-forming tendency of hydrocarbon liquids which tend to so deteriorate, which comprises incorporating in said hydrocarbon liquids a quantity of at least one lower monoalkyl ester of p-hydroxyphenylaminoacetic acid in an amount suflicient to retard said gum formation.

FREDERIC R. BEAN. 

